CARA Science: Python

Summary

Python was a 0.75-meter telescope which detected and characterized
anisotropy in the cosmic microwave background (CMB) radiation
at sub-degree angular scales. The experiment operated
successfully for five summer seasons at the Pole. In the first three years
of observations, the telescope was outfitted with a four
pixel bolometric photometer operating at 90 GHz. In the last two years of
observations, the photometer was replaced by a two pixel HEMT
amplifier-based radiometer operating at 40 GHz.

Results

The same region of sky, uncontaminated by any known foregrounds, was
observed at both 40 and 90 GHz. A joint analysis of the 40 and 90 GHz data
sets confirms that the anisotropy observed is consistent with that
expected from the CMB. In its last year of observations the Python
experiment sampled approximately 600 square degrees of sky
(see Figure 1).
The large sky coverage, high signal to
noise ratio, and low contamination due to foregrounds allowed a reliable and
robust determination of the CMB power spectrum
as shown in Figure 2.

Python has detected structure in the CMBR on angular scales of
0.91°, 2.75°, and 5.5°, at two different wavelengths,
and at more than a hundred points on the sky. Its data are among the
most extensive, most precise, and best confirmed measurements yet
made of intermediate-scale anisotropy.